This invention relates to trench shoring assemblies and, in particular, to a type of trench shoring assembly known as a trench box and which includes lifting attachments.
Trench boxes are trench shoring assemblies used in excavation work when pipe or conduit is being laid. The trench boxes are comprised of two side walls spaced apart a fixed distance from each other by a plurality of spreader devices affixed to and perpendicular to each side wall. After assembly the trench box is positioned in an excavated hole or trench and pipe is laid within the trench box, and after each length of pipe is laid the trench box is moved along the trench for laying the next length of pipe. The side walls of the trench box keep the excavation area free from earth which may fall or cave into the excavated hole or trench before or during the laying of the pipe.
Prior art trench shoring assemblies have included lifting devices attached to the side walls of trench shoring assemblies. Lifting devices have been secured to a top member of a side wall but are frequently broken away from the side wall during shipment before the trench shoring assembly reaches the excavation area. The present invention allows for the positioning of the lifting rings at the excavation site where the trench shoring assembly or a trench box is assembled. Lifting rings are attached to the side wall connecting means and, in particular, about the spreader devices. By positioning the lifting rings about the spreader devices a raising device may lift the trench box at the strongest point of the trench box.
In accordance with the subject invention there is provided a trench shoring assembly including a pair of spaced wall means, connecting means interconnecting the wall means, and lifting means attached to the connecting means for lifting the assembly upon being connected to a raising means. The lifting means includes a plurality of closed-looped ring members wherein each of the ring members includes a large radius portion engaging the connecting means and a small radius portion for being connected to a raising means.